The filters allow you to "filter" the info displayed, according to specific criteria.
Let's say you wanna find the best sweepstakes offers in the United States.
You enter the "Opportunities" section on your account, click on Offer (on the top menu) and set a filter in "Country" and "Categories".
This means you'll now only see the stats for sweepstakes in the United States.
This will save you lots of time and help you see hyper detailed data.